1. Technical Field
The invention relates to a three-dimensional urban road, specifically to a three-dimensional urban road system capable of intensively utilizing land and avoiding traffic jam.
2. Description of Related Art
Three-dimensional main urban roads can solve problems of traffic jam, parking difficulty and serious inefficiency of the public traffic road resources in large and middle-sized cities, save and intensively utilize land in the urban construction, and also provide an important “space” guarantee to development of the car industry.
Traffic jam and parking difficulty bother large and middle-sized cities all around the world for a long time. It is a commonplace on various media. Large and middle-sized cities with flourishing economy and culture usually face more challenging traffic problems. In particular, many large and middle-sized cities in the world have issued various measures for “forbidding to run” or “limiting in running” because of the traffic jam in recent ten years, aiming at reducing the traffic flow, relieving the traffic pressure on roads and getting smooth roads.
As everyone knows, to disperse the traffic flow, overpasses are built at cross roads in the cities this is because overlarge traffic flow causes jams at many cross roads. Then, overpasses appeared at all major cross roads in cities. Those almost connected but completely separated intercommunicating flyovers, overpasses or underpasses join roads in the cities together. In large cities, those close overpasses in neighbors are not connected to form a three-dimensional road system because they do not have the function of shunting the vehicles to the destinations. Due to limit in urban space, upward and downward ramps reaching the destinations are only imaginations, so those overpasses disperse and shunt motor cars at the cross roads and then have to “gather” those cars under the ground so as to let the motor cars reaching the destinations run away. Of course, interference with non-motor vehicles and pedestrians become a common thing. However, the rest motor cars and the newly added motor cars pass through this position (generally, there are traffic lights to delay your time and even let you stand in a queue reaching the overpass) and repeat the same mode at the next cross road. This is the common phenomenon of all existing urban traffic roads. The overpasses become the main means and common method to solve the problem of traffic jam in modern large and middle-sized cities, but facing the continuous increase of the traffic flow, they still fail to eradicate the traffic jam because the three-dimensional urban roads and the ground roads cannot run independently and also cannot be organically connected. Moreover, strong promotion of the development of the public transit has become the common cognition of the whole society for a long time, but the implementation faces various difficulties due to restraints of various factors in actual operation, in particular the restraints of the traffic roads in space resources. Therefore, improvement is necessary.